Early Life and Family Background

Kozaburo Hirai was born as the third son among eight siblings in Ino Town, Agawa District, Kochi Prefecture (now Ino Town), a region renowned for its Tosa Washi paper. (His given name was Yasuki, which he changed to Kozaburo in 1951). His father, Sotaro, was a "haikara" (modern and stylish) individual who studied at the Tokyo Prefectural Education Association and, in 1908, even composed the school song for the Simple Commercial School (now Kochi Commercial High School) where he worked as a Japanese language teacher. Around the time Yasuki was born, Sotaro was reportedly engaged in various ventures, including running a paper wholesale business, serving as a director of a sake brewery, and holding a position as a town council member.

Musical Education and Early Career

Hirai grew up in an environment steeped in traditional performing arts and Japanese music from a young age, naturally coming into contact with the violin and organ available in his home. Although he briefly received violin instruction from Tadaaki Ooi (1895–1929), he was largely self-taught when he entered the Instrumental Music Department of the Tokyo Music School in 1929 to study violin. From this period, he began his compositional activities, focusing primarily on vocal music, while studying harmony and counterpoint under Pringsheim. After graduating from the undergraduate program, he proceeded to the composition department of the research course.

Professional Career and Works

Upon completing his studies in 1936, Hirai won first prize at the Japan Music Competition. He immediately became a teacher at his alma mater, but later retired in 1947 after the war, partly due to his involvement in promoting national prestige during wartime with works such as the sacred war song collection "Sekka" (Snow Flowers). Subsequently, he held various prominent positions, including exclusive composer/arranger for NHK, textbook editing committee member for the Ministry of Education, director of the Choral Federation, and professor at Osaka College of Music (1968–79). While his vocal works are primarily known, he is also significant as a pioneer who began working on compositions for traditional Japanese instruments from the late 1940s. Among his piano works, the fantasy "Sakura Sakura" is frequently performed.

Musical Family

Hirai is also known for his musical family:

• His wife, Yumiko (Saeda Hikita), was a violinist and his classmate at the Tokyo Music School, later becoming an emeritus professor at Toho Gakuen School of Music.
• His eldest son, Takeichiro, was a cellist and composer who studied under Casals.
• His second son, Jojiro, was a pianist who served as an emeritus professor at Tokyo University of the Arts and a professor at the Faculty of Music, Seitoku University.
• His grandchildren include:

• Hideaki, a conductor and composer.
• Motoki, a pianist and composer (son of Takeichiro).
• Rie, a pianist and soprano singer (daughter of Jojiro).